In automatic dishwashing machines, the detergent, whether in powder, tablet or gel form, is usually filled manually by the user into the machine, in particular into a detergent holder, before each dishwashing operation.
This filling process is inconvenient, with the problem of exact metering of the detergent and possible spillage thereof, for powder and gel detergents. Even with detergents in tablet form, wherein the problem of accurate dosing is overcome, there is still the necessity of handling the dishwashing detergent every time a dishwashing cycle is started. This is inconvenient because of the usually corrosive nature of dishwasher detergent compositions.
A number of devices are known for holding unit doses of a detergent composition or additive, such as detergent tablets, and for dispensing of such unit doses into a machine.
WO 01/07703 discloses a device for the metered release of a detergent composition or additive into a dishwashing machine having a number of separate sealed chambers for holding the detergent composition or additive and means for piercing the chambers, activated by conditions within the machine.
WO 03/073906 discloses a free standing device for dispensing multiple doses of detergent into a dishwasher. The device has a plate-like construction. A round blister pack, having a plurality of doses arranged around its periphery is loaded into the pack. A winder is then rotated to load mechanical energy into the device sufficient to dispense more than one dose of detergent. A thermally operated latch then moves when the device is subjected to the elevated temperatures within the dishwasher and, in cooperation with a ratchet mechanism, moves the blister pack so that the next dose of detergent is ready for dispensing. In order to dispense the detergent, either the blister pack is pierced, or the dose is ejected from its compartment within the blister pack.
WO 03/073907 discloses a similarly shaped free standing dispensing device. In order to dispense detergent, a lever is manually operated to move a blister pack either to eject the detergent from a compartment within the blister pack, or to pierce the blister pack. A door or flap initially prevents wash liquor within the machine from accessing the exposed detergent. A bi-metallic strip is provided to move the door or flap when the device is exposed to the elevated temperatures during a washing cycle to allow access of the wash liquor to the exposed detergent thereby dispensing the detergent to the machine.
WO2006/021769 relates to an automatic detergent dispensing device that is reactive to temperature changes in the dishwasher.
The prior art devices all react to a simple input from the wash conditions. Normally heat.
WO2005/011462 relates to improved detergent dosing in automatic machine dishwashing. The contents of which are herein incorporated by reference.
This patent discloses the benefits of controlled sequential dosing of treating agents within detergent compositions. The different treating agents within detergent compositions are also often mutually incompatible and interfere with each other, for example the enzymes and the bleach components of most automatic machine cleaning detergents. The controlled sequential dosing is enabled through the use of sensors connected to the washing machine.